1. Field of the Invention
The present invention relates to an antenna frame for an IC card and a process for manufacturing the same. More Particularly, the present invention relates to an antenna frame of an IC card having a plane coil formed by punching or etching a thin metallic sheet in which a conductor is wound by a plurality of times on a same plane, wherein terminals of the plane coil and electrode terminals of a semiconductor element are to be electrically connected to each other, and also the present invention relates to a process for manufacturing such an antenna frame for an IC card.
2. Description of the Related Art
As shown in FIG. 9, an IC card includes: a rectangular plane coil 100 in which a conductor 102 is wound by a plurality of times; and a semiconductor element 104. The plane coil 100 and the semiconductor element 104 are interposed between two sheets of resin films 106 made of polyvinyl chloride (PVC) on a front surface of which characters and others are printed. The two sheets of resin films 106 are made to adhere to each other by an adhesive layer made of polyurethane resin. This adhesive layer also seals the plane coil 100 and the semiconductor element 104.
When the thus formed IC card passes in a magnetic field formed by a card processor, an electric power is generated by electromagnetic induction caused in the plane coil 100 of the IC card. Therefore, the semiconductor element 104 is started by the generated electric power, so that communication can be held between the semiconductor element 104 of the IC card and the card processor via the plane coil 100 which functions as an antenna.
In this IC card, the electrical connection between the plane coil 100 and the semiconductor element 104 can be effected by wires 112, 112 which connect the terminals 108, 108 of the plane coil 100 to the electrode terminals 110, 110.
The plane coil 100 in this IC card is formed by punching or etching a thin metallic sheet so as to reduce the cost of production thereof. It has been found that the plane coil 100 thus formed by punching or etching is difficult to handle by itself, since the conductor line 102 may easily be deformed during the transportation.
In order to solve the above mentioned problems, the inventors have tried to use an antenna frame for IC card as shown in FIG. 10 and obtained some improvement in the handling thereof as compared with a case of handling the plane coil by itself.
FIG. 10 shows an antenna frame 200 which is used for IC card and FIG. 11 shows a terminal portion of the antenna frame 200 shown in FIG. 10. The plane coil 216 is provided with respective end portions 218a and 218b of the innermost conductor 226a and the outermost conductor 226b of the plane coil interposing the conductor 226 thereof. These end portions 218a and 218b are formed as wide areas for forming the terminals.
The respective end portions 218a and 218b of the innermost conductor 226a and th outermost conductor 226b is processed by coining to form respective terminals 218a, 218b each provided with a bonding area.
Thus, a bonding operation can easily be performed by using a bonding machine to obtain the electrical connection between the terminals of the semiconductor element which is mounted on the plane coil 216 and the terminals 218a, 218b of the plane coil 216.
However, as shown in FIG. 12, if the coinning operation is applied to the entire surface of the terminals 218, 218, the peripheral area of coined, widen terminal 218 is enlarged toward the conductor 226. In addition, when the coinning operation is performed, the terminals 218, 218 may easily be shifted to the right and left directions (the direction indicated by an arrow B in FIG. 12). Thus, there is a possibility that the terminals 218, 218 comes into contact with the conductor 226.
In particular, such a shift of the terminals 218, 218 would happen, if the bonding area was formed on the respective terminals 218, 218 of the innermost conductor 226a and the outermost conductor 226b. 
Also, during the plane coil is transported before the coinning process is applied thereto, such a shift of the terminals 218, 218 may easily happen and the terminals 218, 218 may come into contact with the conductor 226, if the respective terminals 218, 218 of the innermost conductor 226a and the outermost conductor 226b are bent to the inward and outward.
An object of the present invention is to provide an antenna frame for an IC card and a process for manufacturing such an antenna frame and an IC card using the antenna frame, in which the terminals of the outermost and innermost conductors of the plane coil defining bonding areas are prevented from coming into contact with the conductor constituting the plane coil.
According to the present invention, there is provided an antenna frame for IC card, said antenna frame comprising: a plane coil formed by punching or etching a thin metallic sheet in which a conductor line is wound by a plurality of times on a substantially same plane, said plane coil having an outermost conductor provided with an outer end portion and an innermost conductor provided with an inner end portion; an outside frame arranged along said outermost conductor line and spaced therefrom by a predetermined interval; an inside frame arranged along said innermost conductor line and spaced therefrom by a predetermined interval; said outer and inner end portions defining outer and inner terminals, respectively, which are used as bonding areas; and supporting sections extending from an end edge of said outer and inner terminals or a position in the vicinity thereof to said outside and inside frames.
The bonding area is to be used for electrically connecting by wire-bonding said bonding area to electrode terminals of a semiconductor element which is to be mounted on said plane coil.
The outer and inner terminals of the plane coil is formed by partially or entirely coinning said outer and inner end portions of the outermost and innermost conductors.
The antenna frame, further comprises a chip mounting area formed on said plane coil and defined by a plurality of looped conductors, the width of said conductors within said chip mounting area is smaller than that of remaining portions of said conductors, so that the width of said conductors within said chip mounting area becomes larger to be substantially the same as the width of said remaining portion of said conductors, after said chip mounting area is deformed to be flat.
The chip mounting area is located near to said respective outer and inner end portions of the outermost and innermost conductors.
The outermost and innermost conductor are provided at said end portion or at a position in the vicinity thereof with terminal forming areas, respectively, to which a coinning is to be applied partially or entirely so as to define respective terminals to be used as bonding areas.
The terminal forming areas has a smaller width than remaining portion of said outermost and innermost conductors. The width of said terminal forming areas is determined so that the width thereof becomes larger to be substantially the same as the width of said remaining portion of said outermost and innermost conductors, after said terminal forming area is deformed to be flat.
The antenna frame, further comprises a chip mounting area formed on said plane coil and defined by a plurality of looped conductors, the width of said conductors within said chip mounting area is smaller than that of remaining portions of said conductors, so that the width of said conductors within said chip mounting area becomes larger to be substantially the same as the width of said remaining portion of said conductors, after said chip mounting area is deformed to be flat. The chip mounting area is located near to said respective terminal forming areas.
According to another aspect of the present invention, there is provided a process for manufacturing an antenna frame for IC card, said process comprising the following steps of:
punching or etching a thin metallic sheet to form a plane coil in which a conductor line is wound by a plurality of times on a substantially same plane, said plane coil having outermost and innermost conductors provided with outer and inner end portions, respectively; an outside frame arranged along said outermost conductor line and spaced therefrom by a predetermined interval; an inside frame arranged along said innermost conductor line and spaced therefrom by a predetermined interval; and supporting sections extending from an end edge of said outer and inner end portions or a position in the vicinity thereof to said outside and inside frames; and
coinning said end portion or a portion in the vicinity thereof of said outermost and innermost conductors to form outer and inner terminals which are to be used as bonding areas.
The punching or etching step comprises a step for forming said end portion or a portion in the vicinity thereof of said outermost and innermost conductors so as to have a smaller width than remaining portion of said outermost and innermost conductors; and the coinning step comprises a step for enlarging the width of said smaller width portion so as to be substantially the same as the width of said remaining portion of said outermost and innermost conductors.
The punching or etching step further comprises a step for forming a chip mounting area on said plane coil and defined by a plurality of looped conductors, the width of said conductors within said chip mounting area is smaller than that of remaining portions of said conductors; and the coinning step comprises a step for enlarging the width of said conductors within said chip mounting area to by substantially the same as the width of said remaining portion of said conductors.
The chip mounting area is formed at a location near to said respective terminal forming areas.
A process for manufacturing an IC card according to this invention comprises:
punching or etching a thin metallic sheet to form a plane coil in which a conductor line is wound by a plurality or times on a substantially same plane, said plane coil having outermost and innermost conductors provided with outer and inner end portions, respectively; an outside frame arranged along said outermost conductor line and spaced therefrom by a predetermined interval; an inside frame arranged along said innermost conductor line and spaced therefrom by a predetermined interval; and supporting sections extending from an end edge of said outer and inner end portions or a position in the vicinity thereof to said outside and inside frames;
coinning said end portion or a portion in the vicinity thereof of said outermost and innermost conductors to form outer and inner terminals which are to be used as bonding areas;
mounting a semiconductor element on a semiconductor element mounting area of said plane coil; and
connecting electrode terminals of said semiconductor element to said bonding areas of said outer and inner terminals by means of wires.